Mobile communication devices have become ubiquitous. Many mobile devices now use third-generation (3G) cell phone technologies. Universal Mobile Telecommunications System (UMTS) is one such technology which is gaining in popularity. UMTS uses Wideband Code Division Multiple Access (WCDMA) as a high speed transmission protocol to communicate with a base station (also called base transceiver station or Node B) in the infrastructure of the network. Networks are formed from adjacent overlapping cells of radio coverage. WCDMA is used to achieve cell separation and thereby minimize problems caused by interference between neighboring cells.
However, a number of problems may exist with the UMTS mobile devices being present everywhere. In particular, there are a number of locations in which it is undesirable for UMTS mobile devices to be able to send or receive calls or messages. Examples of such locations include public or private venues in which privacy, quiet, and/or security may be important, e.g., libraries, laboratories, auditoriums, lecture halls, classrooms, or theatres.
To block the signal, a more powerful signal may be continually broadcast at the frequency that the base station uses to communicate with the UMTS mobile devices (downlink frequency) or at the frequency that the UMTS mobile devices use to communicate with the base station (uplink frequency) to overwhelm the actual communication signal. However, such a technique is power-intensive, especially to cover typical geographical areas over which blocking is desired (and in light of the advanced coding and error-correction techniques developed), making it impractical to use in a self-powered (battery) mobile blocking device. Moreover, this technique is intrusive, blocking all signals at these frequencies—not merely signals between the base station and the UMTS mobile devices. In addition, devices are increasingly capable of operating over different frequency bands, requiring the blocking device to overwhelm signals over multiple different frequency bands.
It is desirable to block communication between the UMTS mobile devices in a particular location and the base station serving the location without engendering the above problems.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted to facilitate viewing clarity. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.